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Purpura and Petechiae

Reviewed and updated by practising UK GPs, overseen by our Clinical Advisory Officer.

🧭 When to suspect

A non-blanching rash is one that does not fade when pressed – confirm it with the glass (tumbler) test, pressing a clear glass firmly over the lesions and watching whether they disappear.

Sizing:

• Petechiae are pinpoint non-blanching spots < 2 mm

• Purpura are 2 mm–1 cm

• Ecchymoses (bruises) are > 1 cm

The single judgement that governs everything is whether the patient is acutely unwell or not:

• An acutely unwell patient with a non-blanching rash has meningococcal sepsis until proven otherwise and needs a 999 ambulance.

• A patient who looks well with an unexplained non-blanching rash is not in the clear – the rash still demands urgent investigation to exclude leukaemia and thrombocytopenia.

Strongly suspect meningococcal disease with any of:

• Purpura (lesions > 2 mm)

• A rapidly spreading non-blanching petechial or purpuric rash

• Any features of meningitis combined with a non-blanching rash

Do not rule out meningococcal disease just because there is no rash, and remember the rash can change from blanching to non-blanching over hours.

Clinical picture Think of Action
Non-blanching rash + systemically unwell (fever, tachycardia, hypotension, cold peripheries, drowsiness) Meningococcal sepsis

• 999 now

• Benzylpenicillin only if transfer delayed

Well child, isolated petechiae/bruising, often days after a viral illness or immunisation Immune thrombocytopenia (ITP) – but leukaemia must be excluded Immediate specialist assessment
Palpable purpura over buttocks/extensor lower limbs + abdominal pain or arthralgia Immunoglobulin A (IgA) vasculitis (formerly Henoch-Schönlein purpura [HSP])

• Urgent paediatric review

• Urine & BP

Petechiae on face/neck, above the nipple line after forceful coughing or vomiting; patient well Mechanical (SVC distribution) Benign if FBC normal – reassure
Crops of purpura on extensor forearms/dorsum of hands in an older adult with fragile skin Senile (actinic) purpura

• Reassure

• Skin protection

Bruising/petechiae in sites or patterns that do not fit the history in a child Consider non-accidental injury Follow safeguarding procedures

Raise suspicion further with relevant risk factors:

• Missed immunisations, asplenia/hyposplenism or complement deficiency, being a student in shared accommodation, recent contact or a local outbreak (meningococcal)

• A personal or family history of bleeding or clotting disorders, anticoagulant or antiplatelet use, liver disease, or recently started medicines (bleeding/thrombocytopenia)

Non-blanching rash on theglass test•petechiae < 2 mm•purpura 2 mm–1 cm•ecchymoses > 1 cmAcutely unwell?•fever, tachycardia, hypotension, coldperipheries, drowsiness•normal vital signs do not excludemeningococcal diseaseMeningococcal sepsis: 999 now•purpura > 2 mm or a rapidly spreadingrash: 999•benzylpenicillin only if transferdelayed: 1.2 g adult or child ≥ 10•withhold only for anaphylaxis topenicillin or cephalosporins•notify the UKHSA health protection teamChild or young person?Immediate specialistassessment for leukaemia•full count, film and specialist opinion,not the platelet number alone•bruising that does not fit the history:safeguarding proceduresAdult: very urgent FBC within48 hours•FBC, clotting screen (PT, APTT) ± bloodfilm•urinalysis ± U&E if a vasculitis issuspectedReading the count and thepatternCytopenias, blasts orcoagulopathyurgent haematology or paediatricreferralNormal FBC, petechiaeabove the nipple lineafter coughing/vomitingmechanical: reassure, safety-netNormal platelets,extensor forearms, olderadult with fragile skinsenile purpura: reassure, skinprotectionPalpable purpurabuttocks/extensor legs +abdominal pain orarthralgiaIgA vasculitis: urgent review; urineand BP for up to 6 monthsIsolatedthrombocytopenia, wellchild after a viralillnessusually ITP, but a specialist mustexclude leukaemiaSafety-net everyone managed athomethe rash can change from blanching tonon-blanching within hoursYESNOYESNOTwo questions, not oneOcean 🌊GPAtlas Ocean 🌊

Source: NICE NG240 · NICE NG12 · NICE NG143


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